Date 如何在颤振中添加年度范围验证
我尝试添加年份范围验证,它必须介于1850年和当前年份之间。我试过了,但没用 这是我试过的代码Date 如何在颤振中添加年度范围验证,date,validation,flutter,flutter-dependencies,year2038,Date,Validation,Flutter,Flutter Dependencies,Year2038,我尝试添加年份范围验证,它必须介于1850年和当前年份之间。我试过了,但没用 这是我试过的代码 String validateestablishedyear(String value) { var date = new DateTime.now(); int currentYear = date.year; int userinputValue = 0; print('currentYear = $currentYear'); print('input
String validateestablishedyear(String value) {
var date = new DateTime.now();
int currentYear = date.year;
int userinputValue = 0;
print('currentYear = $currentYear');
print('input value = $value');
print('value = ${value is int}');
print('value = ${value is String}');
if (value is String && value.length == 0) {
return "Established Year is Required";
} else {
userinputValue = int.parse(value);
}
if (userinputValue < 1850 && userinputValue >= currentYear) {
return "Year must be between 1850 and $currentYear";
}
return null;
}
String validateestablishedyear(字符串值){
var date=new DateTime.now();
int currentYear=date.year;
int userinputValue=0;
打印('currentYear=$currentYear');
打印(“输入值=$value”);
打印('value=${value is int}');
打印('value=${value is String}');
if(值为字符串&&value.length==0){
返回“需要设置年份”;
}否则{
userinputValue=int.parse(值);
}
如果(userinputValue<1850&&userinputValue>=currentYear){
return“年份必须介于1850和$currentYear之间”;
}
返回null;
}
只需按以下方式更改代码
if (userinputValue < 1850 || userinputValue >= currentYear) {
return "Year must be between 1850 and $currentYear";
}
if(userinputValue<1850 | | userinputValue>=当前年份){
return“年份必须介于1850和$currentYear之间”;
}
你的逻辑是错误的。您应该使用|而不是&